Acoustic diaphragm.



c. icooxson. ACOUSTIC DIAPHRAGM.

y APPLICATION FILED MAR. I9 19H.

1,246,552. mmm Nov. 13', 1917.

wnessfs) a; :Mmm Lv' 'larenceil.

UNITED STATES PATENT OFFICE..

I CLARENCE F. COOKSON, OF BROOKLYN, NEW YORK, ASSIGNGR TO ROBERT L.MGELRO'Y',

0F NEW YORK, N. Y.

ACOUSTIC DIAPHRAGM.

Speccation of Letters Patent.

Patented Nov. 13, 1917.

To all whom t may concern:

Be it known that I, CLARENCE F. Cooxsotv, a citizen of the UnitedStates, residing `1n Brooklyn, in the county of Kings and State of NewrYork, have invented certain new and useful Improvements in AcousticDiaphragms, of which the following is a speelcation. This inventionrelates to improvements 1n diaphragms and the method of making the same,and more particularly to such a diaphragm for a phonograph constructedof a laminated fabric. Preferably two layers of vellum or otherparchment are employed, between which is a plurality of layers of tissuepaper having one side coated with an adhesive substance providing meansfor unitingthe layers of tissue and for securing one of .the layers ofvellum on each side thereof. Diaphragme constructed of metal, mica andpaper have. been heretofore employed, but it has been long recognizedthat such diaphragme have a relative slow recovery,

which will not permit the needle actuated thereby to contact with allthe minute variations of the sound grooves of'a record. The presentimprovement, however, consisting ofa laminated fabrica diaphragm, has avery rapid recovery causing the needle to contact with every variationof groove on the record, no matter how Aminute, thereby developingaccurate reproduction and a greater' resonance. Y

*Another object of the present invention, is to devise a simple andinexpensive method of making the laminated fabric diaphragm.

A still further object of the present improvement, is to deviseaiphonograph diaphragm which is constructed of cheap ma` terial andwhich may be manufactured at minimum expense.

Other objects and advantages of the present improvement will be setforth in the following description, one embodiment of which isillustrated in the drawings, in which: c

'.Figure 1, is a ldiagrammatic view of an apparatus for making sheets oflaminated fabric and stamping diaphragms therefrom.

Fig. 2, is a side Ielevation of one ofthe completed diaphragms. Fig. 3,is a side elevation of a diaphragm showing the layers lof fabriccomposing it pulled apart.

Fig. '4 is a diagrammatic view of a sound wave on a record andillustrating the difpressing machine.

ference in the actionv of a needle operated in4 conjunction with alaminated fabric diaphragm and a needle operated in conjunction with ametal, mica or paper diaphragm.

eferr-ing now tb the drawings in detail, in which like reference/numerals designate similar parts, throughout the several fig; ures; 1represents a suitable framework at one end of which eight shafts aremounted in spaced relation and one above the other. These shafts arenumbered 2 to 9 inclusive on the drawing. A roll of fabric, preferablyvellum, 1.0 is revolubly mounted on the shaft 2, the free end of whichis passed between a roller 12, and 'a roller 13, which latter roller hasits lower portion arranged to dip esy within an adhesive substance 14,carried shafts 3 to 8, respectively, the ends of the tissue paper 16being passed between contacting rolls '22 and 23, the roller 23 dippingwithin an adhesive substance carried Within a receptacle 24, the saidrollers 22 and 23, and receptacle 24 similar to and arranged directlybeneath the receptacle 15. The end of the tissue paper 16 is then ledbeneath a guide roller 25 and thence'to the The other live rolls oftissu-e paper have their free end passed through similar devices forcoating theirr 95 these devices being numbered'26 to 30, which undersurface with an adhesive substance,

operate upon the tissue paper rolls 17` to' 2l, respectively. The endsof these rolls of tissue paper are also lcd beneath guide rolls inumbered 3l to 35 respectively and thence to the pressing machine. Asecond roll of vellum 36 is revolubly mounted on the bottom shaft 9,the' free end of which does not pass through an adhesive coating devicebut' and passed between two rolls 38 and 39 re' volub'ly mounted uponshafts 40 and 41, carried in a'framework 42. 1t will be noted that allthe layers of tissue paper are arranged one on top of the other andbetween the layers of vellum, and that the under surface of the sheet ofvellum 2 and of all the sheets of tissue are coated with the adhesivesubstance 14. applied thereto by means ot' the applying devicesheretofore described.

The sheets of tissue and vellum upon passing through the rolls` 38 and39 are pressed together by spring tension accomplished by means ofsprings -l3 strained between set screws 44 and t-he shaft 40 which isvertically movable in a slot 45. Heat is applied to the laminated sheetsby means ot a suitable heating medium 46 contained within the roller 39.Upon leaving the rollers 39 and et() the laminated sheets have been allsecured together by the adhesive substance and the said adhesivetherebetween dried. The unitary structure 47 then passes between afemale die 48 having a plurality of openings 48 therein and a pluralityof cored male dies 49 the cores of which are the desired size of thediaphragm. The male dies 49 are forced downwardly by any suitable means,entering the openings 48 in the female'die 48 cutting out a plurality ofcompleted diaphragms 50, which drop within a collection receptacle 51.

The adhesive substance used within the coating devices may be gum,resin, paratlin wax, shellac, varnish or any resinous gum.

Diaphragms constructed of metal, mica or paper have in practicedemonstrated that they have what is know as a slow recovery. This meansthat the needle upon being moved and released by a sound groove will notbe returned quickly to its original position by the diaphragm forcontact with the neXt portion of the sound wave of the groove.

In Fig. 4 a portion of sound wave is illustrated at 55 which has a largecurve 56, a number of small curves 57 and another large curve 58. Aneedle 59 is illustrated as just leaving the large curve 56. When thisneedle is controlled by a mica, metal or paper diaphragm, upon beingmoved by the curve 5G will recover so slowly that the small waves 57will be skipped in the rapid passage of the record and the needlestrikes the second large sound wave 58 as is illustrated in dotted linesat 60.

When the needle 59 is controlled by a laminated diaphragm, however, uponbeing struck by the large curve 56 will be returned to its originalposition so quickly by the diaphragm that it will slide down the slope5G of the large curve 56 and pass over all the small curves57 as isillustratedvinA dotted lines at 61.

The laminated diaphragm will interpret all the phrasing of the noteswhich the ing apparatus, comprising a plurality of interposed layers ofrelatively thick and relatively thin fabric homogeneously securedtogether into a composite single sheet, the tivo outer layers beingthicker than the inner layers.

2. A diaphragm consisting oi' two layers of vellum, a plurality oflayers of tissue paper therebetween, and an adhesive substance unitingthe vellum and tissue.

$3. A diaphragm consisting of two layers ot vellum, a plurality oflayers of tissue paper therebetween, and an adhesive substance appliedto one side ofl the vellum and tissue paper for uniting them.

il. A diaphragm for use in. sound transmitting, receiving, recording, orreproducing apparatus, comprising interposed layers of relatively thickfabric and layers et relatively thin fabric, the thin fabric being 'oita. dilerent material than the thick, and an adhesive substance appliedto one surface of each of the layers for securing them together.

5. A diaphragm consisting of two layers of relatively thick fabric and aplurality of -layers of relatively thin fabric therebetween, and anadhesive substance uniting the said thick and thin layers of fabric.

6. [i diaphragm consisting ot a plurality of interposed layers of vellumand tissue paper secured together.

7. vdiaphragm consisting of two layers of relativel thick fabric and sixlayers of relatively tliin fabric therebetween, and an adhesivesubstance uniting the layers.

8. A diaphragm consisting ot two layers of vellum, six layers of tissuetherebetween, and an adhesive substance uniting the vellum and tissue.

9. A diaphragm consisting of a plurality of interposed layers oit vellumandtissue paper and an adhesive substance for uniting them.

10. A diaphragm consisting of a plural' vellum and layers ot tissuepaper secured thereto.

Clie RENCE F. COOKSN. Witnesscsz H. A. ParrrsoN, H. D. PENNEY.

